The present invention relates to photographic cameras of the type provided with a shutter release, a shutter, means responding to activation of the shutter release by causing the shutter to perform a retarded opening movement, and means operative when activated for causing the shutter to close, to thereby terminate the exposure. Cameras of the type in question are also provided with automatic exposure-control circuitry operative for selective exposure durations in dependence upon scene brightness levels.
When the scene brightness level is within a first range, the automatically selected exposure durations will be so short that, during a substantial part of the exposure, the shutter will be in the process of moving from its closed to its open position.
When the scene brightness level is within a second range, the automatically selected exposure durations will be so long that, during a substantial part of the exposure, the shutter will already be in its fully open setting.
If the light-integrating circuit of the automatic exposure control means incorporates only a single light-sensitive element to be used for scene brightness levels within both the first and the second range, there may be difficulty in providing a single light-sensitive element whose sensitivity is appropriate for the brightness levels of the two brightness ranges.
It would be desirable to alternatively use for the light-integrating circuit two different light-sensitive elements, one having a sensitivity appropriate for the one range, the other having a sensitivity appropriate for the other range. However, if this is to be done, then problems arise as to how the correct one of the two light-sensitive elements is to be switched into the light-integrating circuit, if the switching-in is to be effected automatically.